Some types of vehicles installed with an engine stop-and-start system, such as an idle reduction control system, have been recently developed for reduction in fuel cost, in exhaust emission, and the like. Such engine stop-and-start systems are designed to, in response to a driver's engine stop operation, shut off fuel supplied to an internal combustion engine of a vehicle so as to automatically stop it. After the stop of the internal combustion engine, these engine stop-and-start systems are designed to cause, in response to a driver's operation to restart the vehicle, a starter to crank the internal combustion engine, thus restarting the internal combustion engine.
In an example of idle-reduction control for manual transmission vehicles, European Patent Application Publication NO. EP 1657436A2 corresponding to Japanese Patent Application Publication NO. 2006-138221 discloses a first technique to detect the driver's depression of the clutch pedal of a target vehicle for disconnecting the internal combustion engine from the transmission during the internal combustion engine being subjected to engine-stop control. Then, the first technique determines that one of engine restart conditions is met, thus restarting the internal combustion engine in response to the determination. This first technique grasps the driver's depression of the clutch pedal as the driver's engine-restart request. This properly adjusts restart timing of the internal combustion engine, thus improving fuel efficiency.
The European. Patent Application Publication, in order to fulfill more fuel-efficiency improvement requirements, discloses a second technique to detect the driver's depression of the clutch pedal so as to determine that one of engine stop conditions is met, thus automatically carrying out engine-stop control of the internal combustion engine.
Under the engine-stop control of the internal combustion engine, the second technique is designed to determine whether the depressed clutch pedal is released by the driver, and, when it is determined that the depressed clutch pedal is released by the driver so as to connect the internal combustion engine to the transmission, to recognize that one of engine-restart conditions is met, thus restarting the internal combustion engine.